Single inclusive hadron production in Deep Inelastic Scattering serves as standard candle observable for probing the 3D partonic structure of proton or nuclear targets. In this talk, I will focus on particle production in the target fragmentation region. At moderate Bjorken-x, this kinematic regime is described by the framework of transverse momentum dependent (TMD) fracture functions. To...
We develop an approach to QCD evolution based on the sequential Born-Oppenheimer approximations that include higher and higher frequency modes as the evolution parameter is increased. This Born-Oppenheimer renormalization group is a general approach which is valid for the high energy evolution as well as the evolution in transverse resolution scale $Q^2$. We found that the evolution equation...
We perform a phenomenological study of helicity-dependent parton distribution functions (hPDFs) using the KPS-CTT small-$x$ helicity evolution equations. Specifically, this new work presents the first study of the influence of polarized proton-proton ($pp$) scattering data whilst simultaneously analyzing inclusive and semi-inclusive deep-inelastic scattering data, all at $x < 0.1$. Polarized...
It is well-known that the back-to-back (correlation) limit of inclusive quark--antiquark dijet production in unpolarized high energy electron--proton collisions can probe the Weizs\"{a}cker-Williams (WW) gluon transverse momentum-dependent distribution (TMD) at small $x$. In this paper, we consider a helicity-dependent version of the same process: we study the double-spin asymmetry for...
